Why you need big electrical to run at less than rated impedance

[Bump4life]

this topic is going in the right direction but there i some detail that i know most of us know but we are leaving out. Box Rise. I saw it mentioned a couple times. So I agree with SNAFU when he says we shouldn't run below manufactures ratings because thats what the amps are designed for. Yes. But quality amps can be pushed a little (not a lot, I use this loosely don't kill me on this haha). Not to say we arent always taking chances when doing this. But it seems it is most common to wire a 1 ohm stable amp to .5 ohm. Bringing box rise into this. Yes you may be wiring at .5 ohm nominal but after all impedence rise (box rise, wire resistance(if much), terminal resistance (if you have one), anything else i forgot) you are most likely above 1 ohm impedence in real world application. If you wire to .35 or .25 ohms then maybe you can be under the min 1 ohm operating range but most of us have way more resistance than we anticipated, thus we are able to run our systems at ".5 ohm". this still requires some electrical upgrades and good wire and such but most can get away with it. When Joe Schmoe goes to do it without the knowledge or insufficient electrical he blows his shit up and wonders why. Just from my experiences, people who blow their amps whether they wire low or not because they are shit or because they used 8 gauge wire for 1000rms or something dumb like that. i mean how many people do you hear on here blowing a DC amp or a sundown amp, or a DD amp, or other quality brands. (maybe i am unaware of this or i miss posts) but I don't see many if any at all. But just a lesson for all of you who don't know, don't do it until you understand the reason for wiring lower, the pros and cons, as stated above by TEAM BASSICK, ( i agree mainly, but if you realize wiring lower puts you at 1 ohm exatly after rise then you wouldnt have a lot of the cons, if not then you are absolutely right), and if you don't mind something going wrong if your calculations are wrong. slowly start to increase volume don't just go out and crank it, see if it turns off before you get to peak volume. If you are careful with it and calculate curent draw and over compensate with electrical no problems should occur hopefully. Guys if I missed anything or wrong info, lets hear it but i hope I didn't do too bad.

edit: just a quick summary of my main point i wanted to get across, if you wire to a lower impedence an the other impendece rise factors put you to the amps safe operating impedence then you are fine. Just hope you have the rise to do so. if not, then you can be asking for trouble.

Disclaimer- there are exceptions to every rule!! of course there are guys that run .5 ohm and lower with no troubles for mainly competition, use info at own risk, otherwise listen to manufacturers ratings!

Edited April 8, 2012 by Bump4life

[TeamHT]

You have a loose understanding of box rise. Rise SHOULD NEVER be used as a saving factor for wiring below recommended impedances, and there is a reason why. Hell, many daily drivers are not always underrated nor should they be required to be. Rise saves setups across the entire world, and the fact is, it will change and vary depending on frequency. Hell, you don't even know what rise is as it is install/vehicle/enclosure/equipment dependent and varies from install to install. Some may experience 1.5x rise at a certain frequency, others 3x, and others 9x. But what happens when the amp actually sees .5 ohm? .35ohm? You think because at ONE NOTE it jumps from .5ohm to 2 ohm that it's saved? Music is different than burping at a tone period.

Edited April 8, 2012 by TeamHT

[STEvil]

let alone when impedance drops below nominal.

[Bump4life]

You have a loose understanding of box rise. Rise SHOULD NEVER be used as a saving factor for wiring below recommended impedances, and there is a reason why. Hell, many daily drivers are not always underrated nor should they be required to be. Rise saves setups across the entire world, and the fact is, it will change and vary depending on frequency. Hell, you don't even know what rise is as it is install/vehicle/enclosure/equipment dependent and varies from install to install. Some may experience 1.5x rise at a certain frequency, others 3x, and others 9x. But what happens when the amp actually sees .5 ohm? .35ohm? You think because at ONE NOTE it jumps from .5ohm to 2 ohm that it's saved? Music is different than burping at a tone period.

yes i am aware that the rise is different among the different frequencies just not too sure so thanks for imput. i guess i can't give you exact numbers. for my instal it works and it was a huge difference going from 1 ohm nominal to .5 ohm nominal with no observed bad effects on amp or sound quality. amp still runs cool. i guess my post is just touching the surface.

let alone when impedance drops below nominal.

how would impedence drop below sepeakers nominal load? if lets say speakers are wired at 1 ohm. how would the amp ever see less than this? never heard of that? anyone else know a thing or 2 about impedence drop?

[ALPINE408]

A big thing about box rise it only works when. The subs are playing a note so if you are wired to .5 ohms everytime the subs stop the amp is still seeing that .5 ohms and can still damage the amp that is bad mmmmkay don't count on box rise for this purpose

Again if I need more power I buy a bigger or a second amp this is the only correct and safe way of adding power anything below manufacturers recommended specss is asking for if the amp blows its your fault the amp is not crap nor is the. Company you are just stupid for risking your equipment for a few hundred more watts

[runner800]

The problem, more than any of the others that occurs is high heat, when resistance is low and curent is high wires and amp internals can get really hot, so big wires and fans are a must especially for a daily system.

[Hotdog]

I run my setup daily at double its 1ohm rating and i am fine with it. At 2ohm i have clamped 3200rms out of my T40001bd. a lot better on electrical and never heats up.

[STEvil]

You have a loose understanding of box rise. Rise SHOULD NEVER be used as a saving factor for wiring below recommended impedances, and there is a reason why. Hell, many daily drivers are not always underrated nor should they be required to be. Rise saves setups across the entire world, and the fact is, it will change and vary depending on frequency. Hell, you don't even know what rise is as it is install/vehicle/enclosure/equipment dependent and varies from install to install. Some may experience 1.5x rise at a certain frequency, others 3x, and others 9x. But what happens when the amp actually sees .5 ohm? .35ohm? You think because at ONE NOTE it jumps from .5ohm to 2 ohm that it's saved? Music is different than burping at a tone period.

yes i am aware that the rise is different among the different frequencies just not too sure so thanks for imput. i guess i can't give you exact numbers. for my instal it works and it was a huge difference going from 1 ohm nominal to .5 ohm nominal with no observed bad effects on amp or sound quality. amp still runs cool. i guess my post is just touching the surface.

let alone when impedance drops below nominal.

how would impedence drop below sepeakers nominal load? if lets say speakers are wired at 1 ohm. how would the amp ever see less than this? never heard of that? anyone else know a thing or 2 about impedence drop?

Impedence can be influenced by either excursion or playing below tuning frequency (thus causing more excursion).